Front-end loader with automatic tilt



July 7., 11970 J. E. MAGNUSON FRONT-END LOADER WITH AUTOMATIC TILT 2 Sheets-Sheet 1 Filed June 7, 1968 INVENTOR. JOHN E. MAGNUSON BY @JQ Q ATTORNEYS y 7. 1970 J. E. MAGNUSON 3,519,156

FRONT-END LOADER WITH AUTOMATIC TILT Filed June 7, 1968 I 2 Sheets-Sheet FIG IIII

INVENTOR. JOHN E. MAGNUSON ATTORNEYS United States Patent 3,519,156 FRONT-END LOADER WITH AUTOMATIC TILT John E. Magnuson, Seattle, Wash., assignor to Pacific Car and Foundry Company, Renton, Wash., a corporation of Washington Filed June 7, 1968, Ser. No. 735,395 Int. Cl. B66f 9/12 U.S. Cl. 214-777 Claims ABSTRACT OF THE DISCLOSURE A reaching type of front-end loader characterized in that the load-handling head automatically tilts forwardly to dump a load by the act of giving reach movement to the boom which carries the head.

This invention relates to a material-handling vehicle, and particularly a vehicle of the general type illustrated and described in my U.S. Pat. No. 3,352,442, issued Nov. 14, 1967.

As with said issued patent, the material-handling mechanism of the present invention provides a boom to which a walking-beam is fulcrumed at approximately the booms mid-length. The boom swings vertically about a root pivot located at the upper end of a mounting leg, and at its outer end connects pivotally with the lower end of a loadcarrying head. Links, one of which is extensible, connect the upper end of the walking-beam to the upper end of the head, and the lower end of the walking-beam to the mounting leg. In the present invention the mounting leg is pivoted for fore-and-aft swing movement to the vehicle frame whereas in said patented structure, the leg is made rigid with the frame. The purpose is to give the boom a reach capability. This, however, is not novel in a generic sense. U.S. Pat. No. 3,024,933 has a swingable mounting leg in an assembly including the boom, walking-beam, head, and links.

An important characteristic in the mechanism of the present invention concerns the geometry of the mounting leg and that of the four-sided figure which includes as two of its sides a portion of such leg and the link connecting such leg with the walking-beam, the relationship being such that as the boom partakes of a reach action by forward swing of the mounting leg there is automatically imparted to the load-carrying head a forward tilting action.

The structure of the present invention is further characterized in that a hydraulic jack functional to raise and lower the boom is more strategically placed than has heretofore been the case.

In the accompanying drawings:

FIG. 1 is a side elevational view illustrating a materialhandling vehicle constructed to embody preferred teachings of the present invention.

FIG. 2 is a top plan view thereof.

As with my above-identified patent, the material-handling structure of the present invention is shown as employing, for its mobile mounting a vehicle having widely spaced traction wheels 10 at one end of a main frame and a swivel-mounted pair of closely adjacent steering wheels 11 at the other end. For purposes of description the traction end of the vehicle will be hereinafter termed the front end. The main frame has a longitudinal principal 12 at each of the two sides, and includes the usual cross members.

Only one of the cross-members is shown in the drawing. Denoted by 13, such cross-member lies immediately to the rear of the live front axle. An upright hydraulic jack 14 foots upon the cross-member, pivoting at 15 for swing movement on the longitudinal median line of the vehicle.

3,519,156 Patented July 7, 1970 "ice The material-handling structure relies for its operation upon four double-acting hydraulic jacks, each of which pivots about a transverse horizontal axis, and namely the jack 14, a pair of jacks 16 which act in concert, and a jack 19. The jacks 16 overlie the frame principals and pivot at 17 from the front end of a respective one of two brackets 18 bolted or otherwise fixedly secured to the frame. Jack 19, like the jack 14, occupies the longitudinal median line of the vehicle.

The pivots 17 occupy a transverse vertical plane spaced well to the rear of the pivot 15. The jacks 16 control the fore-and-aft swing movement of an upright mounting leg 21 which spans the width of the vehicle frame and is pivoted at 22 to the rear ends of the brackets 18. A boom pivots at 23 to the upper end of the mounting leg and is given reach action by the swing movements of the leg. In the rearmost position of the leg the pivot point 23 occupies a perpendicular raised from the pivot point 22. The pivot connections 24 between the outer ends of the jacks 16 and the mounting leg 21 lie somewhat to the front of the boom pivot 23 and are spaced from the pivot axis 22 a distance very nearly the same as the swing radius of the booms root end. This distance also closely approximates the spacing between the pivot points 17 and 22. The importance of the vehicles geometry will be apparent as the description proceeds.

The boom is a fabricated structure comprised of two beams 25 occupying paralleling spaced positions at opposite sides of the vehicles longitudinal median line and rigidified by cross-members at or adjacent each of the two ends. The outer end of the boom connects pivotally, as at 26, with the standard portion 2'7 of a material-handling head, the connection being located adjacent the lower end of the standard. The outer end of the hydraulic jack 14 connects at 28 with the boom at approximately the midlength of the latter.

Between the jack connection 28 and the root pivot 23 of the boom a walking-beam 30 is fulcrurned at 31 to the boom for rocker movement about a transverse horizontal axis. The lower end of the walking-beam connects by a fixed-length link 32 with the mounting leg. The jack 19 links the upper end of the walking-beam to the upper end of the head standard 27, connecting at 34 with the walking-beam and at 35 with the standard.

The material-handling head has a forked load-carrying deck extending forwardly from the bottom end of the standard. The rear portions 36 of the forks are made rigid with the standard. Front portions 37 are pivoted in a manner permitting the same to tilt upwardly while being precluded from tilting downwardly beyond a normal position co-planar with the fixed portion of the deck.

When the head has received a load it is elevated to a level represented, say, by the broken-line position A shown in FIG. 1, incidentto transporting said load to a point of deposit. Reaching destination, the load is deposited by tilting the head. The aforementioned significance of the vehicles geometry is that this tilting is made to occur automatically simply by contracting the reaching jacks which perforce gives to the boom the reaching action usually desired when a load is to be dumped. As such reach motion takes place the arm works toward the perpendicular occupied by the forwardly moving root pivot of the boom, responsively rocking the walking-beam in a counter-clockwise direction as viewed from the vantage point of FIG. 1 so that the upper end of the head standard moves forwardly in a greater degree than the reach travel of the boom. The elevating jack 14 is extended coincident with a contraction of the reaching jacks where it is desired to reach and tilt on the same level.

It is believed that the invention will have been clearly understood from the foregoing detailed description of my now-preferred illustrated embodiment. Changes in the details of construction may be resorted to without departing from the spirit of the invention and it is accordingly my intention that no limitations be implied and that the hereto annexed claims be given the broadest interpretation to which the employed language fairly admits.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In combination with a vehicle main frame, a mounting leg pivoted to the frame for fore-and-aft swing movement between an erect rear position and an inclined front position, a boom pivoted at its inner end to the upper end of the leg for vertical swing movement about a transverse horizontal axis through an arc extending more or less equal distances above and below the horizontal plane occupied by its swing axis, a load-handling head pivoted at its lower end to the outer end of the boom for vertical tilting movements, an upright walking-beam fulcrumed to the boom intermediate the ends thereof for rocker movements about an axis paralleling the booms swing axis, two pivoted links one being extensible and connecting the upper end of the walking-beam to the upper end of the head and the other having a fixed length and connecting the lower end of the walking-beam to the mounting leg at the approximate mid-height of the latter, said extensible link comprising a double hydraulic jack, hydraulic jack means for raising and lowering the boom, and hydraulic jack means for swinging the mounting leg, the geometry of the mounting legs pivot, the booms root-end pivot, the walking-beams rocker axis, and the two pivots of the fixed length link being such that the vehicles load-handling head is tilted forwardly auto- 4 matically by the act of swinging the leg to give a reach movement to the boom. i

2. Structure as claimed in claim 1 in which the jack which raises and lowers the boom connects therewith at a point spaced forwardly from the rocker axis of the walking-beam and foots upon the frame at a point no further to the rear than a perpendicular dropped from said point of the boom connection when the boom is in retracted position.

3. Structure as claimed in claim 2 in which the distance between the booms root-end pivot and the connection with the jack which raises and lowers the boom is less than the horizontal spacing between said jacks frame footing and the mounting legs frame pivot.

4. Structure as claimed in claim 2 in which the boom is comprised of two rigidly connected paralleling beams spaced one from the other at opposite sides of the longitudinal median line of the vehicle, the jack means which raises and lowers the boom being secured to the main frame adjacent the forward end thereof.

5. Structure as claimed in claim 1 in which the mounting leg has a channel shape in horizontal section providing flanges at each of the two sides extending forwardly from a back plate which spans the width of the vehicle frame.

References Cited UNITED STATES PATENTS 2,820,555 1/1958 Lessmann 214-770 3,001,654 9/1961 Albert .214-770 3,352,442 11/ 19 6 7 Magnuson 214-767 HUGO O. SCHULZ, Primary Examiner US. Cl. X.R. 214-770, 778 

